Figure 3.

This figure shows the evolution of the common spatial patterns (CSP) criterion function (in blue line), the symmetrized Kullback–Leibler divergence (sKL) (in red line), the symmetrized beta divergence (in purple line) and the AB-LD divergence (in yellow line), all of them as a function of the components of the spatial filter $\mathit{w}=[w_1,w_2]$ in the two-dimensional case, where it is assumed that ${\parallel \mathit{w}\parallel }_2^2=w_1^2+w_2^2=1$. All the divergences are normalized with respect to their maximum values, and no regularization has been applied. Observe the coincidence of all the critical points. The covariance matrices were generated at random in this experiment.